This invention relates to a high security lock in the nature of a padlock, which is guarded against picking.
The prior art shows numerous attempts to improve the security provided by padlocks. Conventional padlocks have been made heavier and stronger, and provided with shrouds and guards to shield them from attack by cutting and leverage tools. Locks for analogous purposes have been made in special shapes so as to form a protective enclosure about the lock hardware to which they are applied. My prior U.S. Pat. No. 3,820,360 shows a round lock for such a purpose. Such locks, however, are subject to picking, and various measures have been tried to improve their pick resistance, for example, by the use of specially shaped pin tumblers. The present invention provides a lock which is guarded against picking, and which in its preferred form also provides a protective enclosure about the post or other element to which it is applied.